Rhesus disease
Rhesus disease is a condition where antibodies in a pregnant woman's blood destroy her baby's blood cells. Rhesus disease doesn't harm the mother, but it can cause the baby to become anaemic and develop jaundice.
Symptoms of rhesus disease
Rhesus disease only affects the baby. The mother won't experience any symptoms.
The symptoms of rhesus disease depend on how severe it is. Around 50 per cent of babies diagnosed with rhesus disease have mild symptoms that are easily treatable.
Signs in an unborn baby
If your baby develops rhesus disease while still in the womb, they may become anaemic. This is because their red blood cells are being destroyed faster than usual by the antibodies.
Signs in a newborn baby
The two main problems caused by rhesus disease in a newborn baby are haemolytic anaemia and jaundice. Haemolytic anaemia occurs when red blood cells are destroyed.
In some cases, the baby may also have low muscle tone (hypotonia) and they may be lacking in energy.
If a baby has rhesus disease, they won't always have obvious symptoms when they're born. Symptoms can sometimes develop up to three months afterwards.
Causes of rhesus disease
Rhesus disease only happens when the mother has rhesus negative blood (RhD negative) and the baby in her womb has rhesus positive blood (RhD positive).
Rhesus disease is also known as haemolytic disease of the foetus and newborn (HDFN).
The mother must have also been previously sensitised to RhD positive blood.
Sensitisation happens when a woman with RhD negative blood is exposed to RhD positive blood. This usually happens during a previous pregnancy with an RhD positive baby.
If sensitisation occurs, the next time the woman is exposed to RhD positive blood, her body produces antibodies immediately.
If she's pregnant with an RhD positive baby, the antibodies can cross the placenta. This causes rhesus disease in the unborn baby. The antibodies can continue attacking the baby's red blood cells for a few months after birth.
Preventing rhesus disease
Rhesus disease is uncommon these days. This is because it can usually be prevented using injections of a medication called anti-D immunoglobulin.
All women are offered blood tests as part of their antenatal screening to check whether their blood is RhD negative or positive.
If the mother is RhD negative, she'll be offered injections of anti-D immunoglobulin at certain points in her pregnancy when she may be exposed to the baby’s red blood cells.
Treating rhesus disease
If an unborn baby does develop rhesus disease, treatment depends on how severe it is. A blood transfusion to the unborn baby may be needed in more severe cases.
After delivery, the child is likely to be admitted to a neonatal unit (a hospital unit that specialises in caring for newborn babies).
The health professional looking after your baby’s care will discuss treatment options with you.
More useful links
The information on this page has been adapted from original content from the NHS website.
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